The work opens with Serenus asking Seneca for counsel, and this request for help takes the form of a medical consultation. Serenus explains that he feels agitated and in a state of unstable immobility, "As if I were on a boat that doesn't move forward and is tossed about." Seneca uses the dialogue to address an issue that cropped up many times in his life: the desire for a life of contemplation and the need for active political engagement. Seneca argues that the goal of a tranquil mind can be achieved by being flexible and seeking a middle way between the two extremes.  

The first book in the essays of Seneca deals with good and evil. The dialogue is opened by Lucilius complaining with his friend Seneca that adversities and misfortunes can happen to good men too. How can this fit with the goodness connected with the design of providence? Seneca answers according to the Stoic point of view.

Of a Happy Life is an essay written by Seneca around the year 58 AD. It was intended for his older brother Gallio, to whom Seneca also dedicated his dialogue entitled De Ira (On Anger). It is divided into 28 chapters that present the moral thoughts of Seneca at their most mature. Seneca explains that the pursuit of happiness is the pursuit of reason - reason meant not only using logic, but also understanding the processes of nature.  

In On the Firmness of the Wise Man Seneca argues that Stoicism is not as harsh as it first appears. Recalling the figure of Cato the Younger, Seneca argues that Cato as a wise person suffered neither injury nor insult. Although Serenus objects to this paradox, Seneca provides further analogies to emphasize the impervious nature of the wise person. In chapter 5 Seneca distinguishes between contumelia (insults) and iniuria (injuries).

The Enchiridion or Handbook of Epictetus is a short manual of Stoic ethical advice compiled by Arrian, a 2nd-century disciple of the Greek philosopher Epictetus. Although the content is mostly derived from the Discourses of Epictetus, it is not a summary of the Discourses but rather a compilation of practical precepts. Eschewing metaphysics, Arrian focuses his attention on Epictetus's work applying philosophy to daily life. The book is thus a manual to show the way to achieve mental freedom and happiness in all circumstances.